Identification of micro RNAs related to drought stress in wild beet (Beta corolliflora) roots

Abstract Sugar beet ( Beta vulgaris L.) is an economically valuable industrial plant, and drought stress adversely affects sugar quality and yield. Beta corolliflora , a species of the wild beet, shows tolerance to drought stress. It is considered to be drought-tolerant, but the role of microribonucleic acids (miRNAs) in response to drought has not been thoroughly studied in this plant. In this study, the expression profiles of miRNAs in the roots of Beta corolliflora genotype (Drought) and its control (Control) were compared by small RNA sequencing after drought stress treatment. Ultimately, 83 known miRNAs and 148 miRNAs from 70 different miRNA families and their related target genes were identified. Under drought stress, nine miRNAs were upregulated and 10 downregulated in roots. The detected hairpin sequences represented three different small RNA sequences which could be potential miRNA candidates. Gene Ontology analysis (GO) of the target genes indicated that most genes were possibly associated with catalytic activity (molecular function), metabolic processes (biological process), and cellular components. Based on the Kyoto Encyclopedia of Genes and Genomes Enrichment analysis (KEGG), the target genes were highly associated with glycine, serine, threonine, and amino and nucleotide metabolism. In this study, drought stress resulted in limited changes in miRNA expression, indicating restricted regulatory plasticity rather than extensive miRNA reprogramming. These findings provide new information on the molecular mechanisms of drought responses in wild sugar beet, which could be extended to the number of plant drought tolerance genes.